SANTIAGO (Reuters) - The slide in oil prices will probably cut Canadian economic growth by 1/3 of a percentage point in 2015, not the 1/4 point the Bank of Canada estimated in late October, bank Governor Stephen Poloz told Reuters on Friday.

He was speaking on the sidelines of an International Monetary Fund forum in Santiago two days after he held the central bank's policy rate steady at 1 percent. In the interest rate decision, he pointed to the stimulative impact of U.S. economic strength but also to the chilling effect on Canada, a major oil exporter, of cheaper crude.

"When we're predicting growth somewhere between 2 and 2.5 percent, 0.3 (the percentage point reduction from oil) or thereabouts is an important factor. That's downside risk," Poloz said in Santiago.

On Oct. 29, he had estimated the effect of the lower oil price on economic growth to be a quarter point, but prices have continued to slide since then.

He said that while lower oil is negative for the Canadian economy, it is a little positive for the United States, and that it has a spillover effect in the form of stronger U.S. demand for Canadian goods. But the U.S. economy is performing well independently of the oil price, he said, and the lower Canadian dollar is also helping to lift Canadian growth.

"The exchange rate is providing an offset, which is important; and the (Canadian) government has done some new tax changes and infrastructure announcements."

On the Bank of Canada's Dec. 3 statement that household imbalances present "a significant risk to financial stability," Poloz noted that the bank has been worried about imbalances - household debt is near record high levels - for at least a year.

He said household debt has increased in parallel with what he called "overheating in the housing market".

"In our previous statement in October we said that in fact it looked like those imbalances were edging higher, whereas before that it looked like they had stabilized.

"So just by saying 'significant' this week, we're saying well it hasn't really changed lately but it's still significant."

Poloz said that it is difficult to say whether household imbalances are now a bigger consideration in setting rate policy than they have been in the past.

"The way I think about it, the household imbalances will gradually ease, but not by themselves. They will ease because the economy gets stronger, more people get jobs and therefore the income metrics go up faster than the debt metrics."

Since the economic outlook does appear a little more encouraging, he said, that leads to a forecast that these problems will take care of themselves over time.

"But in terms of vulnerability to an external shock we are just as vulnerable as we were before," he added.

In October, Poloz said the bank, generally, will no longer provide forward guidance on the direction and timing of rate changes. He left the door open a crack on Friday to offering guidance again, but suggested it should be used only when really needed.

"We just want to make sure that we have it as a tool in our toolkit and we don't overuse it. I think markets get so used it, that it doesn't have any effect after a while. It's like an addiction. So it's better to put it away and bring it out at a time when it's actually needed."